For most of recorded history, we have witnessed war in the rearview mirror. It took weeks and sometimes months for Mathew Brady’s, and his associates’, photos of  the bloody consequences of Antietam to reach the public.

My social media feed has taken a bloody turn in the last few weeks, and I’m hardly alone. Along with the usual Twitter wisecracking and comments on incremental news, I have seen bodies scattered across fields and hospitals in Ukraine and Gaza. I have read posts from reporters who felt threatened, horrified and revolted.

Geopolitics and the ubiquity of social media have made the world a smaller, seemingly gorier place. If Vietnam brought war into the living room, the last few weeks have put it at our fingertips. On our phones, news alerts full of body counts bubble into our inbox, Facebook feeds are populated by appeals for help or action on behalf of victims, while Twitter boils with up-to-the-second reporting, some by professionals and some by citizens, from scenes of disaster and chaos.

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Ayman Mohyeldin, left, an NBC reporter, at a Gaza hospital. He posted on Twitter about an Israeli strike that killed four boys. Credit: NBC News

Then came radio reports in World War II, with the sounds of bombs in the background, closing the distance between men who fought wars and those for whom they were fighting. Vietnam was the first war to leak into many American living rooms, albeit delayed by the limits of television technology at the time. CNN put all viewers on a kind of war footing, with its live broadcasts from the first gulf war in 1991.

But in the current news ecosystem, we don’t have to wait for the stentorian anchor to arrive and set up shop. Even as some traditional media organizations have pulled back, new players likeVice and BuzzFeed have stepped in to sometimes remarkable effect.

Citizen reports from the scene are quickly augmented by journalists. And those journalists on the ground begin writing about what they see, often via Twitter, before consulting with headquarters about what it all means.

Bearing witness is the oldest and perhaps most valuable tool in the journalist’s arsenal, but it becomes something different delivered in the crucible of real time, without pause for reflection. It is unedited, distributed rapidly and globally, and immediately responded to by the people formerly known as the audience.

It has made for a more visceral, more emotional approach to reporting. War correspondents arriving in a hot zone now provide an on-the-spot moral and physical inventory that seems different from times past. That emotional content, so noticeable when Anderson Cooper was reporting from the Gulf Coast during Hurricane Katrina in 2005, has now become routine, part of the real-time picture all over the web.

The absence of the conventional layers of journalism — correspondents filing reports that are then edited for taste and accuracy — has put several journalists under scrutiny, mostly for responding in the moment to what they saw in front of them.

A reporter from The Wall Street Journal wondered on Twitter what the patients at a Gaza hospital thought of Hamas’s leadership setting up shop in the same location. Ayman Mohyeldin, an NBC News correspondent, was purportedly pulled out of Gaza after posting on Twitter about an Israeli strike that killed four Palestinian boys, accompanied by the hashtag #horror.

Diana Magnay of CNN found herself reassigned to Moscow after she complained on Twitter that she was being threatened by Israelis who were watching the attacks on Gaza from a hill in Israel, calling them “scum.”

And it’s not just a one-way broadcast. Ms. Magnay’s name-calling caused an immediate uproar on the Internet. A Sky News reporter, Colin Brazier, was upbraided on Twitter after going through the belongings of the victims of the downed aircraft in Ukraine during a live shot. He promptly apologized. And after removing Mr. Mohyeldin from Gaza, NBC News was widely criticized on social media, including by many journalists, and it is worth noting that he was reinstated to the assignment. The megaphone goes both ways.

The public has developed an expectation that it will know exactly what a reporter knows every single second, and news organizations are increasingly urging their correspondents to use social media to tell their stories — and to extend their brand. (Unless the reporter says something dumb. Then, not so much.)

Anne Barnard, a reporter for The New York Times covering the Israeli-Palestinian conflict, was criticized on Twitter for … not tweeting. She sees journalistic value in the short-form text service. Interviewed on NPR, Ms. Barnard said: “I think over all it brings more benefits than problems. I think we just — again, we have to remember our primary work is the reporting we’re doing on the ground. You know, our job isn’t to tweet in real time.”

Twitter’s ability to carry visual information has made it an even more important part of the news narrative. A message may be only 140 characters, but we all know a picture is worth many, many words.

Often, it is a single image that comes to represent big, complicated events. The children fleeing napalm in Vietnam, an incinerated soldier along a “highway of death” during the gulf war or the hooded prisoner standing on a box in Abu Ghraib.

Barbie Zelizer, a professor at the University of Pennsylvania’s Annenberg School for Communication, says social media has not fundamentally altered the vocabulary of war.

“It is a difference of degree, not of kind,” she said. “There are more pictures more frequently from more people, but they still serve the same purpose, which is to give us a glimpse, a window, into conflict.”

But we no longer have to wait for those moments.

Tyler Hicks, a longtime photographer for The Times, was at a hotel in Gaza City across from the beach where the four Palestinian boys died. He tweeted the news immediately, took a photo that was hard to glance at and then wrote about what it was like to be standing there.

He said that he felt horrified, but that in a clinical sense he also felt exposed. “If children are being killed, what is there to protect me, or anyone else?”

The act of witness, a foundation of war reporting, has been democratized and disseminated in new ways. The same device that carries photos of your mother’s new puppy or hosts aimless video games also serves up news from the front.

Many of us cannot help looking because of what Susan Sontag has called “the perennial seductiveness of war.” It is a kind of rubbernecking, staring at the bloody aftermath of something that is not an act of God but of man. The effect, as Ms. Sontag pointed out in an essay in The New Yorker in 2002, is anything but certain.

“Making suffering loom larger, by globalizing it, may spur people to feel they ought to ‘care’ more,” she wrote. “It also invites them to feel that the sufferings and misfortunes are too vast, too irrevocable, too epic to be much changed by any local, political intervention.”

So now that war comes to us in real time, do we feel helpless or empowered? Do we care more, or will the ubiquity of images and information desensitize us to the point where human suffering loses meaning when it is part of a scroll that includes a video of your niece twerking? Oh, we say as our index finger navigates to the next item, another one of those.

As war becomes a more remote, mechanized activity, posts and images from the target area have significant value. When a trigger gets pulled or bombs explode, real people are often on the wrong end of it. And bearing witness to the consequences gives meaning to what we see.